NASA Administrator Sean O'Keefe said the agency believes the climate control issue had no bearing on the accident, but that NASA has decided to round up and release e-mails discussing the problem and its possible causes and consequences as an example of the kind of "spirited exchange" that often occurs between engineers.

NASA has taken heat in the press and on Capital Hill for a batch of e-mails written by engineers at Langley Research Center and other NASA field centers raising concerns about a possible breech of Columbia wheel well. Although the engineers characterized their assessments as worst case scenarios, focus has been on the similarity between their hypothetical descriptions and what may have occured during Columbia's Feb.1 reentry.

Asked if he had any reason to believe that the Langley e-mails did not make it further up the NASA chain of command because of management barriers, O'Keefe said "there's nothing I've seen at this juncture that would tell me that there is something clearly amiss."